Like its predecessor, the Pikeman, the main purpose of the Halberdier is countering cavalry units. They can be paired with siege units and protect them from melee cavalry attacks. They become a lot more valuable in the late Imperial Age since at that time gold is usually running very low, often resulting in "trash wars". There, Halberdiers hold advantage against the Hussar, the Magyar Huszar, and they even are valuable against Skirmishers despite the fact that Skirmishers deal bonus damage to them, because they have a minimum range the Halberdiers can exploit. Genitours also receive huge bonus damage from Halberdiers, but they can hit-and-run them, probably making them the best choice against Halberdiers in trash wars.